Colorectal Cancer (CRC) is a major public health issue, affecting more than 1,000,000 people each year and accounting for more than 500,000 deaths each year. CRC is the second leading cause of death due to cancer. In the United States alone, for 2009, approximately 147,000 new cases and over 49,900 deaths due to CRC were reported. There are three forms of CRC: sporadic CRC; hereditary non-polyposis colon cancer (HNPCC), caused by germline mutations in DNA mismatch repair genes; and familial adenomatous polyposis (FAP), due to germline mutations in the APC gene. Sporadic CRC accounts for nearly 85% of cases, while HNPCC accounts for about 5% and FAP accounts for about 1% (Heyer et al., 1999, Oncogene 18:5325-5333).
Clinical management of CRC typically involves surgical resection of tumors often accompanied by chemotherapy. Presently, about 50% of CRC patients die within five years of diagnosis. The lack of reliable screening tests and the ineffectiveness of currently available therapies are major causes of the high mortality rate. There is an urgent need for new clinical approaches for diagnosing CRC, as well as for treatments effective against colorectal cancer tumors that have minimal adverse effects on otherwise healthy tissue.